data_global _amcsd_formula_title 'SiC-IV' loop_ _publ_author_name 'Ramsdell L S' _journal_name_full 'American Mineralogist' _journal_volume 29 _journal_year 1944 _journal_page_first 431 _journal_page_last 442 _publ_section_title ; The crystal structure of alpha-SiC, type IV ; _database_code_amcsd 31 _chemical_formula_sum 'Si7 C7' _cell_length_a 3.073 _cell_length_b 3.073 _cell_length_c 52.78 _cell_angle_alpha 90.0 _cell_angle_beta 90.0 _cell_angle_gamma 120.0 _cell_volume 431.643 _exptl_crystal_density_diffrn 3.239 _symmetry_space_group_name_H-M 'R 3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' 'x,x-y,z' '2/3+x,1/3+x-y,1/3+z' '1/3+x,2/3+x-y,2/3+z' '-y,-x,z' '2/3-y,1/3-x,1/3+z' '1/3-y,2/3-x,2/3+z' '-x+y,y,z' '2/3-x+y,1/3+y,1/3+z' '1/3-x+y,2/3+y,2/3+z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Si 0.0 0.0 0.0 Si 0.0 0.0 0.191 Si 0.0 0.0 0.286 Si 0.0 0.0 0.429 Si 0.0 0.0 0.571 Si 0.0 0.0 0.714 Si 0.0 0.0 0.81 C 0.0 0.0 0.036 C 0.0 0.0 0.226 C 0.0 0.0 0.321 C 0.0 0.0 0.464 C 0.0 0.0 0.607 C 0.0 0.0 0.75 C 0.0 0.0 0.845